The present invention relates to an upsetting press for upsetting or swaging wire segments of predetermined lengths into balls or the like, with the press including a fixed matrix, a stamp holder that is provided for the movable die or stamp and is mounted on a machine frame in such a way as to be displaceable, a cam drive mechanism for the stamp holder, and gripper means that is provided for the wire segments and is controlled in the operating cycle of the press.
Such an upsetting press, which is provided with a cam drive mechanism for the stamp holder that is mounted on a machine frame, is disclosed, for example, in German Offenlegungsschrift No. 26 53 040. This known upsetting press is a so-called miniature ball press, in other words, an upsetting press for stamping relatively small wire segments into correspondingly small balls having a diameter of only several millimeters. With this known press, as the cam drive mechanism for the stamp holder a simple cam is used that is embodied as a so-called cup wheel. Due to the precision of the press that is required when producing balls having such a small diameter, this heretofore known press is necessarily structurally very complicated. However, due to its fundamental structural design, this press is little, or not at all, suitable for processing considerably larger wire segments into balls, pins, and the like. The forces necessary for processing wire segments that are of an order of magnitude of several millimeters to several centimeters would imply a dimensioning of the press of German Offenlegungsschrift No. 26 53 040 that already for economical reasons would no longer be acceptable.
The upsetting presses that are used to convert wire segments of conventional size into balls, pins, and the like therefore have a presser carriage that is mounted in the machine frame in such a way as to be movable back and forth, and that is driven by a drive motor via a crankshaft and connecting rod. With this proven construction, the conversion during swaging of larger wire segments can in particular be carried out without difficulty. Due to the movement principle of the presser carriage that is inherently prescribed due to the crankshaft drive, and due to the stamp holder with its stamp or matrix that is connected to the presser carriage, and due to the necessity of having enough time available for the movement of the gripper means for the wire segments out of the space between the two matrixes after the movable and fixed matrixes have grasped and held the wire segment, it has been known for a long time to displaceably mount the movable matrix, i.e. the matrix holder therefore, on the presser carriage, thereby enabling an increase of the operating cycle of the press.
With the press that is disclosed in German Offenlegungsschrift No. 27 28 647, and which in principle is also the same type of press, the difficulty resulting from the movement principle of the presser carriage is circumvented to a certain extent by mounting the movable matrix holder, with its matrix, independently from the presser carriage in the machine frame in such a way as to be movable back and forth, and by providing the movable matrix holder with a separate drive mechanism that periodically acts upon the matrix holder independently of the presser carriage. In this way, the movement of the matrix holder, with its matrix, can occur over a certain portion of an operating cycle of the press independently of the course of movement of the presser carriage as prescribed by the crankshaft drive.
However, a drawback of this known press is the fact that for the matrix holder, i.e. the movable matrix, two separate drive mechanisms must be provided that have more or less overlapping movement principles and that result in a correspondingly complicated construction of the press. And yet despite all this, such a press, due to the movement principle of the presser carriage that in the end inherently determines the movement of the pertaining matrix, an optimum movement progress of the matrix holder, with its matrix, is not possible over an entire operating cycle, in contrast to upsetting presses that operate with a cam drive mechanism for the matrix holder.
It is an object of the present invention to improve an upsetting press of the aforementioned general type, which in principle is equipped with a cam drive mechanism, to such an extent that the press is structurally simplified, and that the necessary precision of the movement progress of the stamp holder, with its stamp, is assured even at a relatively high output capacity, i.e. high operating cycle of the upsetting press.